There may be no single cause of bipolar disorder (aka manic depression). Instead, research indicates the causes of bipolar disorder are probably a combination of biochemical, genetic and environmental factors that may trigger and perpetuate the chemical imbalances in the brain.
Net worth: $829 million. Telecommunications mogul Strive Masiyiwa is widely regarded as the richest man in Zimbabwe and is one of the richest men in Africa with a net worth of more than US$800 million.
When we think of the worldâs all-time richest people, names like Bill Gates, Warren Buffet and John D Rockefeller immediately come to mind. But few would have thought, or even heard of, Mansa Musa I of Mali â the obscure 14th century African king who was today named the richest person in all history.